I want to edit the site but it's not opening any of the pages on
the home screen?

It should be working now. You forgot to add the closing
</style> tag to your CSS.

I also want to change the front of the logo. What will the code
be for that?

We unfortunately cannot help with every CSS-related query as it
is quite a broad topic and there are many resources available
online. You can also change the font of various elements of your
site from the "Fonts" section of your skin settings.